ARC WELDING METHOD AND ARC SUPPLY SOURCE Russian patent published in 1996 - IPC

FIELD: arc welding with fixed consumable electrodes; welding of long cut workpieces of thickness exceeding 25 mm. SUBSTANCE: method comes to placing consumable electrode in clearance between workpieces to be welded. Electrode is made in form of plate with dielectric coating applied to both opposite sides of plate electrode. Then electrode and workpieces are connected to different poles of supply source and arc is struck between end of electrode pointed to root of weld and workpieces and welding is carried out. Welding arc is supplied from power source with combination external volt-ampere characteristics, arc being started at gradually drooping section of curve with subsequent change to steeply drooping section of curve in range of nominal welding currents. At distance between arc and root of weld exceeding 15 - 20 mm, welding is carried out at gradually rising section of supply source external characteristic curve. Consumable electrode is connected to corresponding pole of supply source in several points arranged at equal distance 1 from each other lengthwise the electrode, with 1 satisfying the condition l≅v_w•τ where v_w-welding speed, τ - time required for heating consumable electrode material by welding current to preset temperature depending on temperature dependence of electric strength of dielectric coating material. In process of movement of arc relative to electrode melt-off front, slope of gradually drooping or gradually rising sections of supply source curve is changed steplessly or by steps. Supply source has transformer-thyristor converter, welding current and voltage transmitters, feedback signal shaping unit, control signal shaping unit, setter and amplitude control discriminator. Circuit makes it possible to change slope of supply source external characteristic curve in process of welding. EFFECT: enlarged operating capabilities. 7 cl, 6 dwg